(1) Field of the Invention:
The present invention relates to a one-component type red color magnetic developer. More particularly, the present invention relates to a one-component type red color magnetic developer having a self-electroscopic property, which comprises particles prepared from a kneaded composition comprising 100 parts by weight of a magnetic powder composed mainly of ocherous gamma-type diiron trioxide, 2.5 to 30 parts by weight of a red azo pigment and 40 to 200 parts by weight of a binder resin, wherein a fixed image of the particles is measured by a color difference meter, the value x is from 0.51 to 0.73, the value y is from 0.22 to 0.40 and the value Y is from 5 to 65%.
(2) Description of the Prior Art:
In the field of the electrophotographic reproduction, there have been proposed various multi-color developing processes in which a peculiar portion of a print, for example, a portion to which an attention should be paid, is developed in a color hue different from that of other portions, for example, a red color.
In case of a so-called two-component type developer among developers used in these multi-color developing prccesses, since toner particles are prepared by kneading a pigment and a resin, separately from a magnetic carrier, the hue of the toner and various developing characteristics are substantially satisfactory. However, in case of a one-component type developer, since a powder of a magnetic material has to be incorporated into developer particles, the hue of the toner and the developing properties are insufficient.
For example, magnetite (triiron tetroxide) which is a magnetic material excellent in the magnetic characteristics is black, and even if a coloring pigment, for example, a red pigment, is incorporated together with this magnetic material, the hue of the developer is blackish and the developer image is obscure.
It is known that magnetite particles are mixed with titanium dioxide to hide and erase the black color of the magnetite particles and a pigment of a desirable hue is further incorporated to form a one-component type color developer. However, when it is intended to sufficiently hide and erase the black color and obtain a desirable color, the magnetic attracting force of the developer is weakened and such troubles as scattering of the toner and fogging in a print are caused.